The 1980s ushered in the era of factory farms, many of which used antibiotics in order to fatten up livestock. Coincidentally, at around the same time, the level of obesity in the United States began to rise. According to the Centers for Disease Control and Prevention, in 1985, all of the states with recorded data had populations in which less than 19 percent of the population was obese. Today, Colorado, the least obese state, counts 20.7 percent of its population as obese; in Mississippi, over a third of adults (34.7 percent) are obese.